1. Field of Invention
The present invention relates to hose couplings. More particularly, the invention is directed to a detachable hose coupling with an improved interlocking U-shaped staple for use in mining applications.
2. Prior Art
There exist a number of detachable coupling designs which include U-shaped interlocking staples. For example, U.S. Pat. Nos. 4,260,184 and 4,923,351 disclose fluid couplings which employ U-shaped staple connectors. The staples interlock male and female coupling pieces when disposed between aligned recessed or grooved surface areas of the exterior of the male piece and a bored surface of the female piece. Thus fair, the U-shaped staple connector has had either a rectangular, circular or D-shaped configuration. The grooved surface of the male piece commonly includes a linear line of contact and the bored surfaces include circular lines of contact. Consequently, the cross-sectional configuration of the U-shaped connector chosen impacted the coupling efficiency.
Each of the prior cross-sectional designs has benefits and disadvantages in certain field applications. Traditionally rectangular and circular cross-sectional U-shaped connectors have been employed in the coupling of the type of present invention due to their ease of manufacture and assembly. However, the rectangular cross-section has beer found to have short life due to fatigue as well as reduced tensile strength. Also, brinelling occurs within the circular bore of the female piece due to angled edges and causes stress points of coupling.
Likewise, the circular cross-section has been found to cause brinelling along a linear contact line of the male piece. However, fatigue and tensile strength of circular cross-sectional type configuration staple are greatly increased.
The advent of the D-shaped cross-section was an attempt to gain efficiencies of both prior configurations by incorporating shape to reduce wear at the points of contact of the staple at the sides and bottom of the grooved surface of the male piece by placing the curved surface of the staple in contact with the curved bored surface of the female piece. While the D-shaped cross-section was an attempt to solve the brinelling problem, it has not been readily accepted into a number of coupling fields.
This has been true in the mining industry which utilizes the rectangular cross-section U-shaped connector on a so-called "Super Stecko" coupling. Presumably, such D-shaped cross-sectional coupling staple connectors have yet to provide a suitable solution to uses in the field of coal mining, wherein coal dust, soot and oil can lodge between tight fittings and cause locking of coupling pieces.
Accordingly, there remains a need to improve detachable hose couplers. The present invention aims to overcome the stated problems in the art.